This invention relates to flame treatment method and apparatus and is particularly concerned with oxy-fuel burners, particularly but not necessarily of the kind that burn particulate coal. Such burners are described in, for example, UK patent specifications 2,099,132 A, 2,146,758 A, and 2,141,815 A and have a configuration of passages to produce a flame that is generally co-axial with the axis of the burner itself. Accordingly, when the burner is employed through a side wall of a furnace or other enclosure to heat a burden at the bottom of the furnace, difficulties can arise in ensuring uniform heating of the given surface area of the burden. (The term `burden` is used herein to mean any solid or liquid substance that is to be heat treated in the furnace.) These difficulties can be amerliorated by arranging for the burner axis to point downwards rather than mounting the burner horizontally. However, such a downward orientation of the burner makes fitment of it to the enclosure more difficult and may not be able totally to solve the problem of localised cold spots being formed.
It is an aim of the present invention to provide an improved flame treatment method and apparatus which makes it possible to ameliorate or overcome the above-described problem, particularly when the source of fuel is particulate coal.